WEBVTT - What were CGA, EGA and VGA? 0:00:04.400 --> 0:00:07.800 Welcome to Tech Stuff, a production from I Heart Radio. 0:00:12.200 --> 0:00:15.080 Hey there, and welcome to tech Stuff. I'm your host, 0:00:15.200 --> 0:00:18.440 Jonathan Strickland. I'm an executive producer with I Heart Radio 0:00:18.480 --> 0:00:21.800 and I love all things tech. And for today's episode, 0:00:21.840 --> 0:00:26.200 we're going to learn about old computer graphics standards. Don't 0:00:26.280 --> 0:00:29.440 run away. This is actually really interesting. We'll learn how 0:00:29.480 --> 0:00:32.159 they became standards in the first place, and what the 0:00:32.200 --> 0:00:34.919 company IBM had to do with all of this, and 0:00:34.960 --> 0:00:38.479 why some early decisions by IBM would lead to the 0:00:38.520 --> 0:00:42.680 company extricating itself from the personal computer business altogether a 0:00:42.680 --> 0:00:45.440 couple of decades later. Now, when I was growing up, 0:00:45.960 --> 0:00:49.600 my family owned a couple of personal computers over the 0:00:49.600 --> 0:00:53.000 course of my childhood. We were in that rare small 0:00:53.120 --> 0:00:56.880 percentage of households with a personal computer back in the 0:00:57.000 --> 0:01:00.480 nineteen eighties, and our first computer was an Apple to 0:01:00.800 --> 0:01:04.680 E with a mono chromatic screen that could only display 0:01:04.920 --> 0:01:08.920 Matrix green style letters. I seem to recall that we 0:01:09.000 --> 0:01:12.760 eventually got a monitor one hundred, which is Apple's color monitor, 0:01:13.280 --> 0:01:16.399 and that was compatible with the two E, assuming that 0:01:16.480 --> 0:01:19.800 you had a too E with the appropriate interface card installed. 0:01:20.240 --> 0:01:23.319 But honestly, that memory might be conflated with the second 0:01:23.520 --> 0:01:28.479 personal computer that my dad would purchase. See, Dad got 0:01:28.520 --> 0:01:31.440 these computers in order to work on his novels. He 0:01:31.480 --> 0:01:34.360 wrote his first couple of books on the old Apple 0:01:34.400 --> 0:01:36.959 to E. I don't know if he still has them, 0:01:37.000 --> 0:01:40.199 but for years he had these novels stored on old 0:01:40.280 --> 0:01:43.560 five and a quarter inch floppy disc and those discs 0:01:43.600 --> 0:01:46.720 could hold about a hundred forty kilobytes worth of information each, 0:01:47.080 --> 0:01:49.640 so to be safe, Dad would typically store two to 0:01:49.720 --> 0:01:53.240 three chapters per disk, since his novels were too long 0:01:53.320 --> 0:01:56.200 to fit onto just one five and a quarter inch disc, 0:01:56.600 --> 0:01:59.200 and the Apple to E had no hard drive. Anyway, 0:01:59.240 --> 0:02:02.480 I digress, So I love thinking about those old times. 0:02:02.520 --> 0:02:07.240 I remember going through sleeves of discs and seeing Dad's 0:02:07.280 --> 0:02:11.240 old novels on there. Our second computer that we owned 0:02:11.280 --> 0:02:14.200 as a family was a two eight six. But what 0:02:14.240 --> 0:02:17.040 does that actually mean. Well, it was a personal computer 0:02:17.200 --> 0:02:21.120 that relied on the Intel eight two eight six central 0:02:21.200 --> 0:02:25.400 processing unit, and it also relied on MS DOSS as 0:02:25.440 --> 0:02:28.760 the operating system. So this computer fell into what we 0:02:28.800 --> 0:02:32.280 would call an IBM compatible computer back in the day. 0:02:32.520 --> 0:02:35.920 It used components and an operating system that allowed it 0:02:35.960 --> 0:02:40.160 to run any software designed for those IBM specific machines. 0:02:40.720 --> 0:02:43.080 I think of this as an interesting part of personal 0:02:43.080 --> 0:02:46.320 computer history and it helps illustrate a shark contrast between 0:02:46.320 --> 0:02:50.919 IBM S strategy and apples. So let's backtrack a little 0:02:50.919 --> 0:02:54.440 bit now, before there were personal computers, Back when you 0:02:54.600 --> 0:02:57.720 needed to work for a special research facility or be 0:02:57.880 --> 0:03:00.239 enrolled in an engineering course in the universe s D, 0:03:00.440 --> 0:03:03.160 or maybe one of a handful of folks who knows 0:03:03.160 --> 0:03:06.040 about computers and works for a big financial company, or 0:03:06.120 --> 0:03:09.200 maybe you're in the military. Back in those days, computers 0:03:09.200 --> 0:03:12.720 really didn't have monitors at all. Computer graphics weren't even 0:03:12.760 --> 0:03:16.080 a thing yet. The computer would typically print out the 0:03:16.160 --> 0:03:19.920 results of a computational process on some sort of paper 0:03:20.080 --> 0:03:23.080 or paper tape. Richard Garriott, who would go on to 0:03:23.160 --> 0:03:26.840 create the Ultimate Computer Game series before You would become 0:03:26.880 --> 0:03:29.959 one of seven private citizens to visit the space Station, 0:03:30.320 --> 0:03:33.120 programmed his first games on a computer that would print 0:03:33.160 --> 0:03:36.960 out each move of his Dungeon Crawler. So imagine a 0:03:37.120 --> 0:03:40.600 top down view of a dungeon Crawler, except you're not 0:03:40.640 --> 0:03:43.120 looking at it on a screen. You actually have to 0:03:43.240 --> 0:03:47.160 print out each move. So you make a move in 0:03:47.200 --> 0:03:50.160 the game, the printer would print out a new display 0:03:50.320 --> 0:03:53.680 of what had happened, and all the figures were represented 0:03:53.680 --> 0:03:57.640 by the basic characters that the printer could replicate, so 0:03:58.040 --> 0:04:00.440 it was limited to whatever the printer could print, and 0:04:00.480 --> 0:04:04.480 that was typically stuff like your standard letters, numbers, and 0:04:04.560 --> 0:04:07.720 symbols on a keyboard. So making a move would require 0:04:07.720 --> 0:04:09.800 the whole system to print out a new picture showing 0:04:09.800 --> 0:04:12.400 the results of that move. So playing the game took 0:04:12.400 --> 0:04:17.400 a while. Obviously the refresh rate was terrible, but eventually 0:04:17.720 --> 0:04:20.600 engineers began to create a way for computers to display 0:04:20.680 --> 0:04:24.039 information over a screen. You might connect the computer to 0:04:24.120 --> 0:04:26.640 a regular old television system and you might have a 0:04:26.640 --> 0:04:30.000 little adapter to do that, or, as would later become 0:04:30.000 --> 0:04:33.560 the norm, you would build computer monitors specifically for the 0:04:33.640 --> 0:04:37.440 systems you were creating, and later we would call these displays. 0:04:37.480 --> 0:04:39.520 But I'm so old i still refer to them as 0:04:39.560 --> 0:04:44.159 computer monitors because that's just how it cemented itself in 0:04:44.240 --> 0:04:47.599 my brain. Obviously, you've got to have some sort of 0:04:47.680 --> 0:04:50.640 bridge for a computer to be able to send meaningful 0:04:50.680 --> 0:04:54.039 information to a display, which will then follow the instructions 0:04:54.160 --> 0:04:57.000 sent by the computer to represent the information to the 0:04:57.080 --> 0:04:59.840 end user. There's got to be some sort of in 0:05:00.000 --> 0:05:03.240 interface to make this happen. On the computer side. As 0:05:03.320 --> 0:05:05.920 well as a port that allows a user to connect 0:05:06.000 --> 0:05:08.039 the computer to the display, there has to be some 0:05:08.080 --> 0:05:10.920 sort of physical connection between the two, and in the 0:05:10.960 --> 0:05:14.800 early days of personal computers, there was no set, standardized 0:05:14.839 --> 0:05:18.200 way to do this. The technology used in one computer 0:05:18.320 --> 0:05:21.520 system wasn't compatible with another, so you couldn't mix and 0:05:21.560 --> 0:05:25.920 match monitors and cables and based systems together. These were 0:05:25.960 --> 0:05:29.640 the wild West days of computing, when making a choice 0:05:29.720 --> 0:05:32.760 as a consumer was complicated because you had no way 0:05:32.800 --> 0:05:35.719 of knowing if the computer you chose was going to 0:05:35.760 --> 0:05:38.320 stand the test of time. You could end up purchasing 0:05:38.320 --> 0:05:41.839 a system at great cost and see the parent company 0:05:41.880 --> 0:05:45.520 crumble and all support for that system would wither away. 0:05:45.880 --> 0:05:48.760 And software developers were affected by this too in a 0:05:48.760 --> 0:05:53.640 big way. Developing software can be an arduous process. Back 0:05:53.640 --> 0:05:57.360 in the early days, it was feasible and even common 0:05:57.720 --> 0:06:00.920 for a single programmer to produce a piece of software 0:06:00.960 --> 0:06:03.760 for a system, But developers had to make the same 0:06:03.800 --> 0:06:06.440 sort of bets that consumers were making. They had to 0:06:06.560 --> 0:06:10.480 choose which systems they would develop four and they would 0:06:10.480 --> 0:06:13.000 hope that they made the right bet and it often 0:06:13.040 --> 0:06:16.000 meant dedicating a lot of their time to learning how 0:06:16.040 --> 0:06:20.240 to program for that particular computers operating system. Since the 0:06:20.279 --> 0:06:23.560 OS of say, an Apple computer was different from that 0:06:23.720 --> 0:06:26.960 of the Texas Instruments trash a D system, which was 0:06:27.000 --> 0:06:30.520 different from the Commodore sixty four, et cetera. So in 0:06:30.560 --> 0:06:33.960 the early days of personal computers, there were many competing 0:06:34.000 --> 0:06:37.200 systems to choose from, both as a consumer and as 0:06:37.200 --> 0:06:41.080 a developer. Apple, Commodore, and Texas Instruments were three of 0:06:41.080 --> 0:06:43.320 the big ones here in the United States, and they 0:06:43.360 --> 0:06:46.440 weren't alone, but they didn't have to contend with a 0:06:46.520 --> 0:06:49.719 really big name in computers for a few years, and 0:06:49.800 --> 0:06:54.400 that was I b M. And that's because initially IBM 0:06:54.480 --> 0:06:59.240 chose to concentrate on its traditional enterprise focused business and 0:06:59.320 --> 0:07:02.080 not really get into the consumer market. They were making 0:07:02.440 --> 0:07:06.520 products and services for other companies, not for end users 0:07:06.560 --> 0:07:09.440 like me and you. Now that would change in nineteen 0:07:09.840 --> 0:07:13.920 one when IBM introduced the IBM Personal Computer or the 0:07:14.120 --> 0:07:18.239 fifty one fifty. IBM didn't invent the term personal computer, 0:07:18.560 --> 0:07:21.400 but the fact that this juggernaut had used the phrase 0:07:21.480 --> 0:07:25.040 for its own product would shape the terminology for computers 0:07:25.080 --> 0:07:29.200 in general, we all know that ultimately the two major 0:07:29.320 --> 0:07:32.960 systems to emerge from those early days were Windows based 0:07:33.080 --> 0:07:37.400 PCs and Mac computers from Apple. These would be the 0:07:37.440 --> 0:07:40.720 two big ones for consumers. There are obviously others out 0:07:40.720 --> 0:07:44.520 there there, Linux systems, for example, but for the majority 0:07:44.520 --> 0:07:48.400 of people out there, it's the Windows based PC and 0:07:48.560 --> 0:07:53.880 Apple's Mac. Well, we call the Windows based machines PCs. 0:07:53.920 --> 0:07:57.760 Because of IBM and its influence, a MAC is a 0:07:57.800 --> 0:08:01.320 personal computer. To a MAC is a PC in the 0:08:01.320 --> 0:08:03.520 sense it's a personal computer, but you wouldn't call it 0:08:03.600 --> 0:08:08.160 a PC typically because to us, PCs means a machine 0:08:08.240 --> 0:08:11.920 built upon ibm s approach, and that leads us into 0:08:11.960 --> 0:08:15.360 the choices IBM made that would ultimately contribute to the 0:08:15.360 --> 0:08:18.960 company getting out of the personal computer business. Further down 0:08:19.040 --> 0:08:21.600 the road. It all comes down to how they chose 0:08:21.640 --> 0:08:23.680 to get into it in the first place. You see, 0:08:24.040 --> 0:08:27.560 when IBM was making the personal computer, the company wasn't 0:08:27.600 --> 0:08:31.640 exactly putting its full support behind that effort in order 0:08:31.680 --> 0:08:34.760 to produce the system cheaply, which would mean the company 0:08:34.760 --> 0:08:37.600 could sell the manufactured systems at a premium and have 0:08:37.679 --> 0:08:40.880 a really sweet profit margin. You know, you you buy 0:08:40.960 --> 0:08:44.880 cheap and you sell high. IBM engineers built the PC 0:08:45.080 --> 0:08:48.720 using off the shelf components. The company didn't build a 0:08:48.800 --> 0:08:53.760 custom made microprocessor or anything. Instead, the original IBM PC 0:08:54.120 --> 0:08:58.320 used an Intel eight chip as the CPU. In a 0:08:58.360 --> 0:09:02.240 similar fashion, the engineers used other standard components to build 0:09:02.240 --> 0:09:06.360 out the PC, and they made an arrangement with Microsoft 0:09:06.400 --> 0:09:09.280 to supply the operating system for this new personal computer. 0:09:09.960 --> 0:09:13.400 And the story behind all of that operating system stuff 0:09:13.480 --> 0:09:17.960 gets really super juicy and bonkers. That has betrayal and backstabbing. 0:09:18.000 --> 0:09:20.640 It's like a Game of Thrones episode. For one thing, 0:09:21.000 --> 0:09:24.640 Microsoft was not the company to originally develop DOSS, but 0:09:24.720 --> 0:09:29.800 it's sure as heck profited from it. But that's another story. 0:09:30.160 --> 0:09:34.120 The operating system that IBM used was called PC DOSS, 0:09:34.120 --> 0:09:38.559 but IBM did not establish an exclusivity agreement with Microsoft, 0:09:38.800 --> 0:09:43.880 and so Microsoft would also develop another OS called MS DOSS, 0:09:43.920 --> 0:09:48.800 which was to all intents and purposes, identical to PC DOSS, 0:09:48.840 --> 0:09:52.360 and it would remain so for several versions. Now, all 0:09:52.400 --> 0:09:55.920 the pieces were in place for IBM's eventual decision to 0:09:55.920 --> 0:09:59.040 get out of the consumer PC market, and it was 0:09:59.720 --> 0:10:01.680 just to the point when it was getting in. You 0:10:01.720 --> 0:10:05.440 see the basic components for the computers were available to anyone, 0:10:05.920 --> 0:10:10.120 and the operating system was likewise available through licensing with Microsoft. 0:10:10.240 --> 0:10:15.080 So an enterprising computer company with much lower operating costs 0:10:15.160 --> 0:10:20.120 than a behemoth like IBM could conceivably swoop in, build 0:10:20.160 --> 0:10:24.920 a reasonable facsimile of an IBM PC machine using similar components, 0:10:25.280 --> 0:10:28.000 and include a licensed version of MS DOSS as the 0:10:28.000 --> 0:10:31.160 operating system. In presto, you have a computer that runs 0:10:31.320 --> 0:10:35.080 just like an IBM PC, including support for all software 0:10:35.120 --> 0:10:38.280 designed for the IBM system, and it's at a fraction 0:10:38.320 --> 0:10:41.520 of the cost. This gave birth to an entire subclass 0:10:41.520 --> 0:10:46.320 of computers called the IBM clones or IBM compatibles. The 0:10:46.360 --> 0:10:48.760 two six I mentioned at the top of this episode 0:10:49.240 --> 0:10:52.480 was just such a machine. We didn't known an official 0:10:52.559 --> 0:10:55.520 IBM Burstal computer, but rather a machine with the same 0:10:55.559 --> 0:10:59.600 sort of guts inside and running MS DOSS. It would 0:10:59.600 --> 0:11:01.920 take a long time for all of this to actually 0:11:01.960 --> 0:11:05.280 catch up to IBM, mind you, it's not like they 0:11:05.320 --> 0:11:09.280 were shot and sunk as soon as they launched. The 0:11:09.320 --> 0:11:12.120 company would ultimately pull back from the PC business, but 0:11:12.160 --> 0:11:14.440 it would stick around long enough to make an enormous 0:11:14.559 --> 0:11:18.920 influence on computers and programming and that includes graphics. When 0:11:18.960 --> 0:11:23.280 the IBM PC debut in nine, the company offered two 0:11:23.320 --> 0:11:27.160 options when it came to graphics. Each was a type 0:11:27.160 --> 0:11:30.160 of circuit board that could be plugged into the motherboard 0:11:30.280 --> 0:11:34.240 of the computer, the sort of an expansion slot. These 0:11:34.240 --> 0:11:37.360 types of cards were called add in boards or A 0:11:37.520 --> 0:11:40.960 I B s, and they represented ways to add capabilities 0:11:40.960 --> 0:11:45.160 to a base computer model. Sometimes those abilities were fairly 0:11:45.240 --> 0:11:49.240 simple additional features. Sometimes, like in this case, they were 0:11:49.320 --> 0:11:52.720 required in order to send images to an external display. 0:11:52.760 --> 0:11:54.920 So without one of these two cards you wouldn't have 0:11:55.000 --> 0:11:59.040 any way of sending information to a computer monitor. The 0:11:59.120 --> 0:12:02.520 first of the two was called the Monochrome Display Adapter 0:12:02.800 --> 0:12:06.479 or m d A. This was a video card installed 0:12:06.600 --> 0:12:11.880 on the PC that would output monochromatic signals to the monitor. Furthermore, 0:12:12.360 --> 0:12:16.760 it didn't do so in a pixel addressable way. So wait, wait, wait, 0:12:16.760 --> 0:12:20.240 what does that mean? All right, So let's remember that 0:12:20.320 --> 0:12:23.720 the images we see on displays and monitors and screens 0:12:23.720 --> 0:12:27.200 like on smartphones are made up of little points of light. 0:12:27.720 --> 0:12:30.640 By changing the brightness and color of those points of light, 0:12:31.080 --> 0:12:34.640 you can create full images. It's not that different from 0:12:34.720 --> 0:12:38.440 the technique used by the famous painter George Serat in 0:12:38.559 --> 0:12:42.200 his famous work A Sunday Afternoon on the Island of 0:12:42.320 --> 0:12:46.760 Lagrange Jatt. In that painting, all the images consist of 0:12:46.840 --> 0:12:49.640 tiny dots of paint, but when you view it from 0:12:49.640 --> 0:12:53.120 a distance, they form the shapes of people spending a 0:12:53.160 --> 0:12:56.400 lovely day at a park along the Sin River. It's 0:12:56.440 --> 0:12:58.520 an example of a style called point to list, and 0:12:58.520 --> 0:13:02.040 it's perhaps the most famous version of this of all time. 0:13:02.160 --> 0:13:06.040 But television's computer monitors and electronic displays like the one 0:13:06.120 --> 0:13:10.200 smartphones use have a similar technique, except they use points 0:13:10.240 --> 0:13:14.240 of light rather than points of paint. Now, as I mentioned, 0:13:14.520 --> 0:13:19.040 the m d A wasn't pixel addressable, and addressability refers 0:13:19.080 --> 0:13:24.560 to the capacity to separately access individual units of something, so, 0:13:24.600 --> 0:13:28.640 in this case pixels. A pixel addressable approach allows the 0:13:28.679 --> 0:13:33.120 computer system to send specific instructions to each and every pixel, 0:13:33.360 --> 0:13:37.199 which in turn lets computers send full images and graphics 0:13:37.200 --> 0:13:40.720 to a connected monitor. But m d A didn't have 0:13:40.880 --> 0:13:44.160 that capability, so you couldn't send a black and white 0:13:44.160 --> 0:13:47.480 photo to display on a connected monitor. The m d 0:13:47.600 --> 0:13:52.600 A was dedicated purely to text mode. The screen consisted 0:13:52.679 --> 0:13:56.480 not of pixels so much as it did of character cells. 0:13:56.520 --> 0:13:59.560 So imagine a box that's large enough to hold the 0:13:59.679 --> 0:14:03.679 large ist text character, like an uppercase G or W 0:14:04.040 --> 0:14:08.080 or something. Now imagine that the entire screen is a 0:14:08.120 --> 0:14:12.000 grid of those boxes. Each box is exactly the same shape, 0:14:12.040 --> 0:14:14.960 so it can a lot for the largest of characters 0:14:15.040 --> 0:14:17.920 inside of it. But that's all they can fit inside. 0:14:17.920 --> 0:14:21.920 Each box is one character. You couldn't create more complex images, 0:14:22.240 --> 0:14:26.080 only pictures that consisted of those basic characters, just like 0:14:26.160 --> 0:14:29.160 the old printers that I mentioned earlier that Richard Garriott 0:14:29.200 --> 0:14:32.320 had been playing with. Well, with these displays you could 0:14:32.320 --> 0:14:37.160 get really good resolution on those characters, so the images 0:14:37.200 --> 0:14:41.280 were crisp and clear. The pictures, the text was incredibly 0:14:41.320 --> 0:14:45.000 clear to read. It was very simple too. With these displays, 0:14:45.040 --> 0:14:48.040 you could get really good resolution on those characters. The 0:14:48.120 --> 0:14:52.240 text is crisp and clear. And that was a big 0:14:52.320 --> 0:14:54.600 drop because a lot of these computers were meant to 0:14:54.680 --> 0:14:58.920 go towards small businesses, where presumably the applications you're running 0:14:58.960 --> 0:15:02.960 are mostly text based. There were some tradeoffs because the 0:15:03.000 --> 0:15:06.480 screen was made up of a grid of equal sized boxes, 0:15:06.520 --> 0:15:10.720 and each of those boxes could contain one character. Every 0:15:10.800 --> 0:15:14.080 letter would use up the same amount of space on 0:15:14.160 --> 0:15:18.160 the screen. So an upper case W, which is about 0:15:18.160 --> 0:15:20.720 as wide as it gets, would take up the same 0:15:20.760 --> 0:15:23.320 amount of space as an upper case I. Now I 0:15:23.360 --> 0:15:26.040 don't mean that the upper case I would be wide, 0:15:26.800 --> 0:15:30.120 but rather it would occupy a spot that would be 0:15:30.440 --> 0:15:34.480 surrounded by an invisible box the same size as the 0:15:34.520 --> 0:15:37.360 invisible box that goes around the upper case W. So 0:15:37.400 --> 0:15:40.920 you get this weird spacing between letters in the same word, 0:15:41.280 --> 0:15:44.760 if you're using a collection of wide and narrow letters, 0:15:45.400 --> 0:15:50.680 it would just look off. It's called monospace font. It's 0:15:50.800 --> 0:15:52.720 it's the same sort of thing that you would see 0:15:52.960 --> 0:15:56.960 with a lot of printers and typewriters because they were 0:15:57.040 --> 0:16:01.040 limited to having all of their stamps at the same size, 0:16:01.120 --> 0:16:04.840 even if the letters were different sizes. In contrast, most 0:16:04.880 --> 0:16:08.680 fonts we use today are proportional fonts, which means individual 0:16:08.760 --> 0:16:12.200 characters are given space proportional to their own size, so 0:16:12.240 --> 0:16:14.840 you don't get these odd gaps between letters that should 0:16:14.840 --> 0:16:17.000 be right next to each other. But that was just 0:16:17.120 --> 0:16:20.040 one option for the IBM PC. The other option had 0:16:20.120 --> 0:16:23.800 direct addressability for pixels. It also had support for color, 0:16:23.880 --> 0:16:26.880 so you could have color graphics with this version, and 0:16:26.960 --> 0:16:30.080 it was called c g A and we'll talk about 0:16:30.120 --> 0:16:41.080 it more after the break. So c g A stands 0:16:41.120 --> 0:16:45.440 for Color Graphics Adapter, and describing this technology will also 0:16:45.480 --> 0:16:47.720 require us to examine a couple of other sets of 0:16:47.760 --> 0:16:50.600 standards that affected the graphics that displayed on old c 0:16:50.800 --> 0:16:55.560 g A systems. C g A had big limitations had 0:16:55.640 --> 0:16:59.800 compared to graphics cards today, they seem absolutely stone a. 0:17:00.480 --> 0:17:04.760 The c g A system could support four different modes officially, 0:17:05.040 --> 0:17:08.960 but clever programmers figured out ways to boost this. We'll 0:17:08.960 --> 0:17:12.600 get into that. There were two text modes and two 0:17:12.640 --> 0:17:16.879 graphic modes for the c g A card. The first 0:17:17.040 --> 0:17:20.800 text mode supported four bit color and could display up 0:17:20.840 --> 0:17:24.720 to forty characters per line, with twenty five lines making 0:17:24.800 --> 0:17:28.080 up the total screen space, so twenty five like you 0:17:28.080 --> 0:17:31.800 could stack twenty five vertically or you could stack forty 0:17:31.840 --> 0:17:36.880 horizontally across the screen. The pixel aspect ratio was one 0:17:37.200 --> 0:17:40.359 to one point two. But what does that mean. Well, 0:17:40.440 --> 0:17:44.720 these pixels were not perfect squares. They were actually taller 0:17:45.080 --> 0:17:48.639 than they were wide. With that ratio of one for 0:17:48.760 --> 0:17:52.160 width to one point two for height, this would mean 0:17:52.160 --> 0:17:55.040 that the visual resolution of the screen was more like 0:17:55.160 --> 0:17:59.480 three twenty by two forty In actuality, it was three 0:17:59.520 --> 0:18:03.280 twenty by two hundred. So why the three forty, Well, 0:18:03.600 --> 0:18:08.080 because the pixels were longer than they were wide. If 0:18:08.119 --> 0:18:11.520 you were clever with the way you create your computer graphics, 0:18:11.880 --> 0:18:15.320 it would seem almost like you had stacked more pixels vertically, 0:18:15.920 --> 0:18:17.959 and you could take advantage of things and make a 0:18:17.960 --> 0:18:20.520 picture that had that sort of look as if it 0:18:20.560 --> 0:18:23.680 was a resolution of three twenty by two forty. However, 0:18:24.240 --> 0:18:27.160 if you needed to cut things short and the ratio 0:18:27.280 --> 0:18:30.080 just wasn't working for you, it would become a detriment, 0:18:30.200 --> 0:18:32.800 not an asset. However, if you do the math, you'll 0:18:32.840 --> 0:18:36.159 see that this means every character on screen would have 0:18:36.280 --> 0:18:39.840 eight pixels dedicated to it. And here's how I did that. 0:18:39.880 --> 0:18:43.040 You just take the resolution with that's three twenty pixels. 0:18:43.400 --> 0:18:45.280 You divide that by the number of characters that could 0:18:45.320 --> 0:18:48.840 fit on one line. Remember it's forty characters across, so 0:18:49.000 --> 0:18:52.160 three twenty divided by forty you get eight. The same 0:18:52.240 --> 0:18:55.480 is true vertically. You can have twenty five characters stacked 0:18:55.520 --> 0:18:58.119 from top to bottom on the screen, and the vertical 0:18:58.200 --> 0:19:01.520 resolution is two hundred pixels top to bottom. Two hundred 0:19:01.560 --> 0:19:06.640 divided is eight. So each character and the adapter supported 0:19:06.680 --> 0:19:11.359 two fifty six different characters could use eight pixels for 0:19:11.440 --> 0:19:16.040 display purposes. The four bit color part also needs explaining. 0:19:16.200 --> 0:19:20.159 So a bit is a single unit of computer information, 0:19:20.320 --> 0:19:23.160 and we represent it as either a zero or a one, 0:19:24.119 --> 0:19:27.200 So that means a bit has one of two possible 0:19:27.240 --> 0:19:29.639 states at any given time. You can think of it 0:19:29.680 --> 0:19:34.720 as off or on, zero or one. We have four 0:19:34.800 --> 0:19:37.120 bits for four bit color, so that means we can 0:19:37.160 --> 0:19:41.160 think of having to the possible number of states per bit. 0:19:41.760 --> 0:19:45.440 Raised to the power of four, that's equal to sixteen. 0:19:45.880 --> 0:19:50.640 So four bit color could support sixteen different colors total, 0:19:51.040 --> 0:19:56.679 not all at once, but total, like, that's the number 0:19:56.720 --> 0:20:02.040 of colors this display could show. In text mode, programmers 0:20:02.080 --> 0:20:05.800 could choose a foreground and background color, choosing from those 0:20:05.880 --> 0:20:10.159 sixteen pre made colors. In addition, a bit for the 0:20:10.240 --> 0:20:12.920 foreground color could be dedicated to make the character blink, 0:20:13.000 --> 0:20:16.439 so you can have blinking text in the foreground the 0:20:16.680 --> 0:20:21.359 blinking bit the bit responsible for that blinking command, was 0:20:21.440 --> 0:20:24.560 repurposed for the background color, and it's served as an 0:20:24.560 --> 0:20:29.639 intensity bit instead. Intensity essentially means how dark or bright 0:20:29.920 --> 0:20:33.760 that particular color happens to appear. The second text mode 0:20:34.280 --> 0:20:38.160 was an eighty by twenty five four bit color mode, 0:20:38.800 --> 0:20:42.639 so that meant you could fit eighty letters across in 0:20:42.680 --> 0:20:47.920 a line twenty five lines per screen. These letters were 0:20:47.960 --> 0:20:50.920 half as wide as the forty by twenty five versions. 0:20:51.200 --> 0:20:54.040 Makes sense, right, you could fit twice as many across 0:20:54.119 --> 0:20:56.439 the screen, they must be half as wide as the 0:20:56.480 --> 0:21:01.760 forty five. The pixel ratio the this would create for 0:21:01.800 --> 0:21:05.760 a visual representation of the resolution was six forty by 0:21:05.840 --> 0:21:09.439 four eighty. Now, in reality, those pixels again were taller 0:21:09.440 --> 0:21:12.879 than they were wide. In fact, they were notably taller 0:21:12.920 --> 0:21:16.200 than they were wide, so the real resolution, the true 0:21:16.240 --> 0:21:19.119 resolution was six forty by two hundred, but it looked 0:21:19.119 --> 0:21:23.560 like six forty eight. More programs were written in this 0:21:23.640 --> 0:21:26.960 mode because that you could fit way more text on 0:21:27.000 --> 0:21:30.000 a screen than you could with the forty five mode. 0:21:30.520 --> 0:21:34.080 It was less chunky, but most text based programs relied 0:21:34.240 --> 0:21:38.320 on the eighty by twenty five approach. If you were 0:21:38.400 --> 0:21:41.240 using a word processor or something, this was the style 0:21:41.600 --> 0:21:43.920 that you were most likely looking at. That being said, 0:21:43.920 --> 0:21:46.320 the resolution of text on a C G A machine 0:21:46.760 --> 0:21:48.959 was lower than what you would have found on the 0:21:49.040 --> 0:21:52.800 monochromatic M D A computers, so it was a tradeoff 0:21:52.920 --> 0:21:57.719 You could have a c g A ibm PC running 0:21:57.720 --> 0:22:00.199 on this eighty by twenty five text mode for a 0:22:00.240 --> 0:22:03.600 specific program and it would be fine. It just wouldn't 0:22:03.600 --> 0:22:06.480 be as crisp and clear as the monochromatic m d 0:22:06.640 --> 0:22:12.040 A text specific machines onto the graphics modes. However, that's 0:22:12.040 --> 0:22:15.639 what we're really interested in, right, What actually made the images, 0:22:16.080 --> 0:22:21.680 not just the text on these computers. Well, the graphics 0:22:21.680 --> 0:22:24.600 mode for the c g A machine had, like I said, 0:22:24.640 --> 0:22:27.800 two different modes to it, two different official modes to it. 0:22:28.080 --> 0:22:32.480 One was a three twenty by two hundred resolution, but 0:22:32.720 --> 0:22:35.280 the pixel ratio was one to one point two, so 0:22:35.400 --> 0:22:38.520 again it looked more like three by two forty. This 0:22:38.560 --> 0:22:42.520 mode could display up to four colors at any one time, 0:22:42.800 --> 0:22:46.880 using one of two pre selected palettes. This is why 0:22:46.880 --> 0:22:49.080 if you ever look at old c g A games, 0:22:49.119 --> 0:22:51.800 they all start to look really similar. They're all using 0:22:51.800 --> 0:22:56.080 the exact same colors for colors. The programmers were working 0:22:56.119 --> 0:22:59.639 under some really tight restrictions. The first palette of colors 0:22:59.640 --> 0:23:05.160 include did black, green, red, and yellow. This was palette zero. 0:23:05.560 --> 0:23:10.879 The second palette, a k A Palette one had black, cyan, magenta, 0:23:11.000 --> 0:23:14.640 and white. Now, as you can imagine it's pretty tough 0:23:14.720 --> 0:23:18.040 to create good graphics with this limited color selection. Now 0:23:18.720 --> 0:23:22.480 on top of that, programmers could use low intensity or 0:23:22.560 --> 0:23:27.200 brightness or high intensity or brightness, So that would add 0:23:27.240 --> 0:23:31.080 another variation. And I've seen the same screen presented in 0:23:31.680 --> 0:23:36.760 both palettes at both levels of intensity, and there are differences, 0:23:36.880 --> 0:23:39.720 like you can get a very different effect going from 0:23:39.760 --> 0:23:42.719 one to the other. So programs had a little bit 0:23:42.760 --> 0:23:46.800 of flexibility, but not by much. In both palettes, black 0:23:47.040 --> 0:23:51.359 is color zero, and color zero was actually customizable. You 0:23:51.359 --> 0:23:54.760 could swap it out. You could choose one of the 0:23:54.800 --> 0:23:58.600 other fifteen colors that c g A supported and use 0:23:58.720 --> 0:24:01.879 that as color z Yerow. Black would no longer be used. 0:24:02.200 --> 0:24:04.560 The flip side of this is that the new color 0:24:04.680 --> 0:24:07.520 would replace color zero in all of the image, So 0:24:07.800 --> 0:24:11.160 if you wanted the image to have black in it, 0:24:11.160 --> 0:24:13.600 it would get replaced by whatever color you had now 0:24:13.720 --> 0:24:17.639 designated as color zero. If you wanted to have green 0:24:17.800 --> 0:24:22.200 included with your white, cyan, and magenta, then it would 0:24:22.240 --> 0:24:25.520 mean that if you had a scene with a night sky, 0:24:25.920 --> 0:24:28.600 that night sky is going to be green because it 0:24:28.640 --> 0:24:31.840 would normally be black, but you've designated that color to 0:24:31.880 --> 0:24:35.680 go to green. Instead of black. So yeah, very limited. However, 0:24:35.760 --> 0:24:39.480